1H-Indole, 4-(1-methyl-3-piperidinyl)-, (E)-2-butenedioate (2:1) 4-(1-Methyl-3-piperidinyl)-1H-indole (E)-2-butenedioate (2:1) 4-(1-Methylpiperidin-3-yl)-1H-indole fumarate 83363-32-0